The present invention relates to a method for drying a ceramic compact containing a gelable binder.
There have been known gelable binders which are a kind of organic binders and which are blended in a body so as to improve flowability and moldability by imparting flexibility to the body when the body is prepared. The gelable binders have a property of gelating by being heated at predetermined temperatures or higher. A gelable binder is used for giving a property of maintaining the configuration to a compact having a portion being prone to deform by drying shrinkage of a thin wall, or the like. A compact is obtained by molding a body containing such a gelable binder into a desired configuration. The compact is generally subjected to hot-air drying in a drying process, followed by the next process.
However, the conventional hot-air drying has a problem of causing deformation by drying shrinkage because vaporization of water in a compact and gelation of a gelable binder proceed simultaneously by exposing the compact to the dry, hot air having low humidity in a stage before the gelation of the gelable binder is completed, i.e., in a stage in which the compact is still prone to deform.
Further, in the hot-air drying, since the hot air blowing to the compact has a directivity, it is difficult to dry the whole compact evenly, and thereby the compact is prone to have nonuniformity of drying, which is one of the serious factors of deformation caused to a product in a firing process.
The present invention is achieved in consideration of such a conventional situation. The object of the present invention is to provide a drying method which seldom causes deformation of a ceramic compact containing a gelable binder by dry shrinkage or generation of nonuniformity of drying.